title: Cyclopropane-aldehyde annulations at quaternary donor sites: stereoselective access to highly substituted tetrahydrofurans.
abstract: A diastereoselective synthesis of pentasubstituted tetrahydrofurans via a Lewis acid catalyzed (3 + 2)-annulation of quaternary donor site cyclopropanes and aldehydes is described. The reaction is catalyzed by Sn(OTf)(2), SnCl(4), or Hf(OTf)(4) in yields up to 95% and diastereomeric ratios as high as 99:1.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
authors.forename: Austin G
authors.initials: AG
authors.lastname: Smith
authors.forename: Michael C
authors.initials: MC
authors.lastname: Slade
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Johnson
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D003521:Cyclopropanes / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D003521:Cyclopropanes; D005663:Furans; C030797:cyclopropane